Membrane topography of HLA I, HLA II and ICAM-1 is affected by IFN-γ in lipid rafts of uveal melanomas

Andrea Bodnár(1), László Bene(2), Sándor Damjanovich(1,2), György Vámosi(1), Zsolt Bacsó(2), János Aradi(3), András Berta(4) and Judit Damjanovich(4)

(1) Cell Biophysics Research Group of the Hungarian Academy of Sciences (2) Dept of Biophysics and Cell Biology; (3) Dept of Biochemistry and Molecular Biology and (4) Dept of Ophtalmology; Medical and Health Scince Center, University of Debrecen

The lateral distribution and colocalization of HLA I, HLA-DR and ICAM-1 proteins was studied for the first time in the plasma membrane of two human uveal melanoma cell lines, OCM-1 and OCM-3. Our fluorescence resonance energy transfer and confocal laser scanning microscopic experiments revealed that these molecules are mostly confined to the same membrane regions, where they form similar protein patterns (homo- and hetero-associates) to those found previously on other cell types of lymphoid as well as colorectal carcinoma origin. Confocal microscopic colocalization experiments with GM1 gangliosides and the GPI-anchored CD59 molecules showed enrichment of HLA I, HLA-DR and ICAM-1 molecules in specific membrane domains (lipid rafts) excluding the transferrin receptor. IFN-γ remarkably increased the expression levels of these molecules and rearranged their association patterns, which can affect the adoptive immune response of effector cells.

Email: bodnar@jaguar.dote.hu

Address: Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, , Nagyerdei krt. 98., H-4012 Debrecen, Hungary